Geolocation and edge logic in NextJS - Step-by-Step Execution

Concept Flow - Geolocation and edge logic

User Request

↓

Edge Middleware runs

↓

Check Geolocation from request

↓

Apply Edge Logic

↓

Modify Response or Redirect

↓

Send Response to User

The flow starts with a user request hitting the edge middleware, which checks geolocation data. Based on location, it applies edge logic or defaults, then sends the response.

Execution Sample

NextJS

import { NextResponse } from 'next/server';

export function middleware(request) {
  const country = request.geo?.country || 'US';
  if (country === 'FR') {
    return NextResponse.redirect(new URL('/fr', request.url));
  }
  return NextResponse.next();
}

This middleware checks the user's country from geolocation and redirects French users to a French page, others continue normally.

Execution Table

Step	Request Geo Country	Condition (country === 'FR')	Action	Result
1	FR	True	Redirect to /fr	User redirected to /fr
2	US	False	Continue	User proceeds normally
3	undefined	False	Continue	User proceeds normally with default US

💡 Execution stops after redirect or continuing to next middleware/handler.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3
country	undefined	FR	US	US (default)

Key Moments - 2 Insights

Why does the middleware redirect only when country is 'FR'?

Because the condition checks if country === 'FR' (see execution_table step 1). Only then it triggers a redirect; otherwise, it continues.

What happens if geolocation data is missing?

The code uses 'US' as a default (execution_table step 3), so it continues without redirect.

Visual Quiz - 3 Questions

Look at the execution table, what is the action when the country is 'US'?

A Redirect to /fr

B Redirect to /us

C Continue normally

D Throw an error

💡 Hint

Check execution_table row 2 under 'Action' column.

At which step does the condition country === 'FR' evaluate to true?

A Step 1

B Step 2

C Step 3

D Never

💡 Hint

See execution_table 'Condition' column for each step.

If the default country was changed to 'DE', what would happen at step 3?

A Redirect to /de

B Continue normally

C Redirect to /fr

D Throw an error

💡 Hint

Default country affects variable_tracker and condition check in execution_table step 3.

Concept Snapshot

Next.js Edge Middleware can access user geolocation via request.geo.
Use this to apply edge logic like redirects or content changes.
Check if request.geo?.country matches a target country.
Redirect or modify response accordingly.
Fallback to default if geolocation is missing.
This runs at the edge, before page rendering.

Full Transcript

This example shows how Next.js Edge Middleware uses geolocation data from the request to decide what to do. When a user sends a request, the middleware runs first at the edge. It checks the country code from request.geo. If the country is 'FR', it redirects the user to the French page '/fr'. If the country is 'US' or geolocation is missing, it continues normally. The variable 'country' tracks the detected or default country. This logic helps serve location-specific content quickly and efficiently at the edge.

Practice

1. What is the main purpose of using geolocation in a Next.js app with edge logic?

easy

A. To manage user authentication

B. To improve server-side rendering speed

C. To store user data securely

D. To customize content based on the user's location

Solution

1. Step 1: Understand geolocation usage

   Geolocation helps identify where a user is accessing the app from.

2. Step 2: Connect geolocation with edge logic

   Edge logic runs code near the user to customize responses quickly, often based on location.

3. Final Answer:

   To customize content based on the user's location -> Option D

4. Quick Check:

   Geolocation = Customize content [OK]

Hint: Geolocation customizes content by user location [OK]

Common Mistakes:

• Confusing geolocation with authentication
• Thinking geolocation improves rendering speed directly
• Assuming geolocation stores user data

2. Which of the following is the correct way to access the user's country code in Next.js middleware using edge logic?

easy

A. const country = request.geo.country

B. const country = request.location.countryCode

C. const country = request.headers['x-country']

D. const country = request.geoCode.country

Solution

1. Step 1: Recall Next.js middleware geo API

   Next.js provides a geo object on the request with location info.

2. Step 2: Identify correct property for country code

   The correct property is request.geo.country to get the country code.

3. Final Answer:

   const country = request.geo.country -> Option A

4. Quick Check:

   request.geo.country = country code [OK]

Hint: Use request.geo.country to get country code [OK]

Common Mistakes:

• Using incorrect property names like geoCode or location
• Trying to get country from headers without custom setup
• Confusing geo with location objects

3. Given this Next.js middleware code snippet, what will be the redirect URL if the user is from 'US'?

export function middleware(request) {
  const country = request.geo?.country || 'unknown';
  if (country === 'US') {
    return Response.redirect(new URL('/us-home', request.url));
  }
  return Response.next();
}

medium

A. /unknown

B. /home

C. /us-home

D. /

Solution

1. Step 1: Check country value from request

   The code sets country to request.geo?.country or 'unknown'. For a US user, it is 'US'.

2. Step 2: Analyze redirect condition

   If country is 'US', the middleware redirects to '/us-home'. Otherwise, it continues normally.

3. Final Answer:

   /us-home -> Option C

4. Quick Check:

   Country 'US' triggers redirect to /us-home [OK]

Hint: Country 'US' redirects to /us-home [OK]

Common Mistakes:

• Ignoring the redirect condition
• Assuming default path is used for US
• Confusing Response.next() with redirect

4. Identify the error in this Next.js middleware code that tries to redirect users from Canada to '/ca-home':

export function middleware(request) {
  const country = request.geo.country;
  if (country = 'CA') {
    return Response.redirect(new URL('/ca-home', request.url));
  }
  return Response.next();
}

medium

A. Missing optional chaining on request.geo

B. Using assignment '=' instead of comparison '===' in the if condition

C. Response.redirect should be Response.redirectTo

D. URL constructor is used incorrectly

Solution

1. Step 1: Check the if condition syntax

   The condition uses country = 'CA', which assigns 'CA' instead of comparing.

2. Step 2: Identify correct comparison operator

   It should use === to compare values, not =.

3. Final Answer:

   Using assignment '=' instead of comparison '===' in the if condition -> Option B

4. Quick Check:

   Use '===' for comparison, not '=' [OK]

Hint: Use '===' for comparison, not '=' [OK]

Common Mistakes:

• Confusing assignment and comparison operators
• Thinking Response.redirectTo exists
• Overlooking optional chaining necessity

5. You want to serve different homepage content for users from Europe and Asia using Next.js edge middleware. Which approach correctly implements this logic?

export function middleware(request) {
  const country = request.geo?.country || '';
  const europeCountries = ['FR', 'DE', 'IT'];
  const asiaCountries = ['JP', 'CN', 'IN'];

  if (europeCountries.includes(country)) {
    return Response.redirect(new URL('/eu-home', request.url));
  } else if (asiaCountries.includes(country)) {
    return Response.redirect(new URL('/asia-home', request.url));
  }
  return Response.next();
}

hard

A. This code correctly redirects European and Asian users to their homepages

B. The includes method cannot be used on arrays in middleware

C. The country variable should be fetched from request.headers instead

D. Response.redirect requires a status code as second argument

Solution

1. Step 1: Verify country detection and arrays

   The code safely gets country with optional chaining and defines arrays for Europe and Asia countries.

2. Step 2: Check redirect logic

   It uses includes to check membership and redirects accordingly, else continues normally.

3. Final Answer:

   This code correctly redirects European and Asian users to their homepages -> Option A

4. Quick Check:

   Array.includes works and redirects correctly [OK]

Hint: Use array.includes to check country and redirect [OK]

Common Mistakes:

• Thinking includes is not allowed in middleware
• Trying to get country from headers without setup
• Assuming Response.redirect needs status code